1. Field of the Invention
The present invention relates generally to avionics systems, and more particularly to utilizing an enhanced grammar input for a voice recognition system to provide commands in response to a user's voice input based on the aircraft's dynamic, current state.
2. Description of the Related Art
Voice Recognition algorithms rely upon grammar and semantics to determine the best possible text match(es) to the uttered phrase(s). The aircraft operating environment is very unique in the grammar rules that are followed, and the grammar suite is rather extensive including “words” that represent unusual collections of characters (e.g. intersection or fix names). These factors make it difficult to develop a comprehensive grammar set for use on an aircraft, and this represents one of several significant challenges to bringing Voice Recognition to the cockpit.
Others have attempted to use dynamic grammar for enhancing voice recognition systems. For example, U.S. Pat. No. 6,125,341, entitled “Speech Recognition System and Method,” issued to H. F. Raud et al, discloses a speech recognition system having multiple recognition vocabularies, and a method of selecting an optimal working vocabulary used by the system. Each vocabulary is particularly suited for recognizing speech in a particular language, or with a particular accent or dialect. The system prompts a speaker for an initial spoken response; receives the initial spoken response; and, compares the response to each of a set of possible responses in an initial speech recognition vocabulary to determine a response best matched in the initial vocabulary. A working speech recognition vocabulary is selected from a plurality of speech recognition vocabularies, based on the best matched response.
U.S. Pat. No. 6,745,165, entitled “Method and Apparatus For Recognizing From Here To Here Voice Command Structures in a Finite Grammar Speech Recognition System,” issued to J. R. Lewis et al, discloses a method and system that uses a finite state command grammar coordinated with application scripting to recognize voice command structures for performing an event from an initial location to a new location. The method involves a series of steps, including: recognizing an enabling voice command specifying the event to be performed from the initial location; determining a functional expression for the enabling voice command defined by one or more actions and objects; storing the action and object in a memory location; receiving input specifying the new location; recognizing an activating voice command for performing the event up to the new location; retrieving the stored action and object from the memory location; and performing the event from the initial location to the new location according to the retrieved action and object. Preferably, the enabling-activating command is phrased as “from here . . . to here”. The user specifies the new location with voice commands issued subsequent to the enabling command. To reduce the occurrence of unintended events, these voice commands are counted so that if they exceed a predetermined limit, the action and object content is cleared from memory.
U.S. Pat. No. 7,010,490, entitled “Method, System, and Apparatus for Limiting Available Selections in a Speech Recognition System,” issued to L. A. Brocious et al, discloses a method and system for completing user input in a speech recognition system. The method can include a series of steps which can include receiving a user input. The user input can specify an attribute of a selection. The method can include comparing the user input with a set of selections in the speech recognition system. Also, the method can include limiting the set of selections to an available set of selections which can correspond to the received user input. The step of matching a received user spoken utterance with the selection in the available set of selections also can be included.
Generally, any variation in the grammar implemented in a voice recognition system is based upon previous commands or states computed within the voice recognition system. Such types of systems would have limited applicability in an avionics environment because the grammar in avionics systems is very detached and fragmented.